<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        span {
            width: 200px;
            height:300px;
            background-color: red;
            display:inline-block;  /*将行内元素转换为行内块元素*/
        }
        label {
            width: 200px;
            height:300px;
            background-color:green;
           /* display: block; */  /*将行内元素转换为块级元素*/
        }
        div{
            width: 200px;
            height:300px;
            background-color:yellow;
            display:inline;   /*将块级元素转换为行内元素*/
        }
    </style>
</head>
<body>
      <span>你好</span>
      <label>lable</label>
      <div>这是一个div</div>
</body>
</html>